This invention relates in general to the field of infrared imaging and, more particularly, to an infrared transmissive window used for infrared imaging.
Over the past several years, infrared radiation technology has evolved very quickly. One aspect of this evolution has been in the area of thermal imaging. Thermal imaging systems generally include infrared radiation components, such as an infrared transmissive window through which infrared radiation enters the system, an infrared detector which detects the infrared radiation that passes through the window, a circuit that processes the detected infrared radiation information, and a monitor that displays infrared radiation information received from the circuit. These infrared radiation components cooperate to display a view of a scene based on the thermal energy emitted by objects in the scene. These thermal imaging systems have been generally adequate for their intended purposes, but have not been satisfactory in all respects.
A problem with existing thermal imaging systems is that the infrared transmissive windows are generally uniform in visual appearance, and are thus lacking in aesthetic appeal. This is particularly a problem when the thermal imaging system is included in a vehicle. Thermal imaging systems that operate within a vehicle generally include an infrared transmissive window in the grille of the vehicle. The window has a blank appearance which gives the impression that something is missing from the window or grille structure.
Another problem with existing thermal imaging systems is that some infrared transmissive windows reflect visible light in a manner which draws more attention to the window than desired. There is a need for a window which blends better with its surroundings.
From the foregoing, it may be appreciated that a need has arisen for an apparatus and method that provide improved control over the manner in which an infrared transmissive window handles visible light. According to the present invention, an apparatus and method are provided to address this need, and involve: generating a visible image by causing visible radiation to cooperate with structure of an element in a manner so that the visible image is visible at a location spaced from the element; and passing infrared radiation through the element and the structure thereof without significant change in the infrared radiation.